1. Field of the Invention
The present invention relates to inkjet recording devices, and more specifically, to an inkjet recording device whereby a liquid drop of recording liquid such as ink is discharged from a recording head to a recording surface of a recording medium such as a recording paper so that an image is recorded.
An inkjet recording device such as an inkjet printer is frequently used for personal use more than an electronic picture type image forming device. Because of this, there is a demand for the device main body to be miniaturized and a necessary space be made narrow. It is effective to improve a device layout in order to correspond to such a demand. Hence, a device having various device layouts exists. For example, FIG. 1, FIG. 2 and others of the Japan Laid-Open Patent Application No. 2003-326787 disclose an inkjet printer having a device layout wherein a paper feeding tray is provided at a rear surface side of the device and image recording is performed on a recording paper (recording medium) while the recording paper fed from the paper feeding tray is conveyed to a front surface side. This device layout has been widely applied to an inkjet printer being in the market. In addition, FIG. 5, FIG. 6, FIG. 7 and others of the Japan Laid-Open Patent Application No. 2003-182106 disclose an inkjet printer wherein a paper feeding tray is provided at a lower part of a recording part having a recording head. In this inkjet recording device, a recording paper part just after being fed from the paper feeding tray is curved approximately 180 degrees to a moving direction and then is conveyed linearly toward a paper discharge tray. After that, an image is recorded at a position facing the recording paper part linearly conveyed, by the recording head.
However, in the above mentioned inkjet recording devices, the image is recorded on an upper surface of the discharged recording paper and the discharged recording paper is stacked from the bottom in order. Therefore, the line order of the discharged papers is opposite to the printing order. Because of this, when a document having plural pages is printed, since normally printing is performed in page order, the user has to reverse the line order of the discharged papers. Hence, there is a disadvantage in that this is inconvenient for the user.
This disadvantage can be solved, in the above mentioned inkjet recording devices, by positioning the recording head to the opposite side against the conveying path of the recording paper. However, under this layout, the ink is discharged from the recording head to an upper part in an upward vertical direction. Therefore, it is necessary to have a recording head whereby the ink is adhered to the recording paper at high precision with a strong discharging force for making the ink adhere to the recording paper against gravity. Hence, it is difficult to realize this.
An inventor of the present invention worked out a device layout wherein ink is discharged onto a fed recording paper from a horizontal direction or a vertically higher direction than the horizontal direction so that an image is recorded, then the recording paper is curved until the recording surface of the recording paper faces a lower part in the downward vertical direction, and then the recording paper is discharged. Under this device layout, since the line order of the discharged papers is the same as the printing order, the above-mentioned problem can be prevented. Furthermore, since the recording head by which the ink can be discharged in the vertically lower direction or discharged in the horizontal direction can be applied, it is easy to realize this.
However, the following problem was found by the inventor to realize the device layout according to further studies of the inventor.
That is, since normally a large friction force occurs between the curved recording paper part and a guide surface for curving the recording paper part, a conveying load is made large. Because of this, in a case where the above-mentioned device layout is applied, it is necessary to apply a stronger conveying force to the recording paper as compared with the layout whereby the recording paper is linearly conveyed. Furthermore, in order to obtain the stable conveyance of the recording paper, it is desirable to give a conveying force to the recording paper at least in the vicinity of the curved recording paper part. In addition, it is necessary to correspond to the demand for miniaturization of the device in order to realize this device layout, and therefore it is desirable to convey the recording paper in a state where the recording paper part just after the image is recorded is curved. Thus, in order to realize the above-mentioned device layout, it is required to give a strong conveying force to the recording paper part in a state where the ink is not dried completely. Furthermore, in a case where such a strong conveying force is given, a slight slip between a surface moving member such as a conveying roller for giving the conveying force and the recording paper may occur. Accordingly, if the strong force is given from the recording surface side in the state where the ink is not dried completely on the recording paper, the image is rubbed by the slip so that the image quality is degraded.